Effects of acute or short-term oral sodium bicarbonate supplementation on high-intensity intermittent exercise performance and physiological responses in team-sport athletes: a systematic review and meta-analysis.

BACKGROUND: Sodium bicarbonate (NaHCO3) ingestion can induce extracellular alkalosis, but its effects on high-intensity intermittent exercise (HIIE) performance in team sports remain unclear. This study evaluated the effects of acute or short-term NaHCO3 ingestion on HIIE performance and physiological responses in team-sport athletes. METHODS: This systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 statement. Six databases were searched from inception for randomized controlled trials, with the final search conducted on July 26, 2026. HIIE performance outcomes were synthesized using a covariance-adjusted three-level random-effects meta-analysis, whereas blood lactate, bicarbonate ( HCO 3 - ), and pH were analyzed separately using two-level random-effects models. Subgroup, meta-regression, and sensitivity analyses were conducted. Risk of bias was assessed using the Cochrane Risk of Bias 2 (RoB 2) tool, and certainty of evidence was evaluated using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. RESULTS: Twenty studies involving 241 athletes contributed 53 performance effect sizes. NaHCO3 ingestion had a small beneficial effect on HIIE performance (Hedges' g = 0.23, 95% CI: 0.07 to 0.39, P = 0.008; 95% PI: -0.22 to 0.68; I2 = 37.36%). No clear effects were identified for repeated-sprint performance, mean power, intermittent endurance, or work capacity, and neither subgroup analyses nor meta-regression identified significant moderating effects of sex, dose, ingestion frequency, formulation, exercise phase, or rest/work ratio. NaHCO3 ingestion increased post-exercise blood lactate (MD = 1.73 mmol/L, 95% CI: 0.97 to 2.49), HCO 3 - (MD = 2.73 mmol/L, 95% CI: 2.16 to 3.30), and pH (MD = 0.050, 95% CI: 0.025 to 0.075). The performance findings remained stable across alternative correlation assumptions, one-primary-outcome-per-study analyses, and leave-one-study-out analyses. Certainty of evidence was low for HIIE performance and HCO 3 - and very low for blood lactate and pH. CONCLUSION: Acute or short-term NaHCO3 ingestion may provide a small average improvement in HIIE performance and increase post-exercise blood lactate, HCO 3 - , and pH. However, the prediction interval crossed zero, and no consistent moderators were identified. Its practical use should therefore be individualized according to the exercise task, performance response, and gastrointestinal tolerance. SYSTEMATIC REVIEW REGISTRATION: https://www.crd.york.ac.uk/PROSPERO/view/CRD420261424869, identifier: CRD420261424869.